You have a great opportunity to try for in-flight shots. Observe in the evening, the state of the light that they start to fly. You could try for an image, but it will probably be too fast for your reactions.

You need to observe at the same light level at dawn. With a tripod, pre-focused, you will be able to see them coming in to land. It will take many attempts, as you only get a few minutes each day. You will have to use flash too.

What a great find! But if you never saw them before, perhaps they simply weren't there before? Just this week I discovered bats roosting in my backyard. In 20 years of living here, this is the first time they have ever roosted here.http://www.projectnoah.org/spottings/150...